Cleaning unit in electrophotographic copier

ABSTRACT

A cleaning unit for an electrophotographic copier is provided to remove toner and developing material from a photo-sensitive material from which a developed image has been transferred and includes a housing having an opening facing the photo-sensitive material. A main blade member is provided in the housing of the cleaning unit and has an upper portion which abuts against the photo-sensitive material through an opening of the housing to scrape the toner and developing materials off the photo-sensitive material. The cleaning unit further includes a receiving blade covering the lower portion of the opening, and having an upper end portion abutted against the photo-sensitive material to allow the toner and developing material scraped off by the main blade to fall into the opening and a film-shaped reinforcing member bonded to the surface of the receiving blade facing the inside of the housing to prevent deformation of the receiving blade.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an electrophotographic copier in which anelectrostatic latent image, formed on a photo-sensitive material, isdeveloped with toner, and the developed image is transferred onto atransferring sheet to obtain a copied image. And more particularly, thisinvention relates to a cleaning unit in the copier which is adapted toremove toner and developing materials from the photo-sensitive materialfrom which a developed image has been transferred.

2. Description of the Related Art

In general, in an electrophotographic copier, a predeterminedelectrostatic latent image is formed on a photo-sensitive materialprovided on a rotating photo-sensitive drum. The latent image is thendeveloped with toner, and the developed image is transferred onto atransferring sheet to obtain a copied image. In general, after thedeveloped image has been transferred onto the transferring sheet, thetoner and developing materials remain on the photo-sensitive materialnecessitating removal from the photo-sensitive material with a cleaningunit.

A conventional cleaning unit, such as that shown in FIGS. 6, 7, and 8,has a housing 51 with an opening 51a. The opening 51a faces aphoto-sensitive material 10a provided on the outer cylindrical wall of aphoto-sensitive drum 10. A cleaning member, namely, a main blade 52 isdisposed in the upper part of the housing 51 in such a manner as totouch the surface of the photo-sensitive material 10a in order to scrapethe remaining toner and developing material off the surface of thephoto-sensitive material 10a. A receiving blade 53 of thermo-plasticpolyurethane rubber or similar material is provided in such a manner asto cover the lower portion of the opening 51a of the housing 51. Theupper edge of the receiving blade 53 abuts against the photo-sensitivematerial 10a so that all of the toner and developing materials scrapedoff with the main blade 52 fall positively into the housing 51 withoutscattering therefrom.

If the electrophotographic copier is shipped out of the factory with theupper edge of the receiving blade 53 abutted against the surface of thephoto-sensitive material 10a, then the surface of the photo-sensitivematerial 10a can deteriorate during transportation. The photo-sensitivematerial 10a is especially sensitive to deterioration when the copier istransported over a long distance with the environmental conditionschanging greatly.

In order to overcome this difficulty, a method has been employed inwhich the electrophotographic copier is shipped out of the factory withthe receiving blade 53 held away from the photo-sensitive material 10a.For instance, as shown in FIG. 9, the receiving blade 53 is coupled to asupport 54 which can be detachably secured to the housing 51 of thecleaning unit, and when the copier is shipped out of the factory, thesupport 54 is disconnected from the housing 51 (as indicated by thetwo-dot chain line in FIG. 7). Accordingly, during the transportation ofthe copier, the receiving blade 53 does not contact the photo-sensitivematerial 10a and the photo-sensitive material 10a is less likely to bedeteriorated.

This method is nevertheless disadvantageous because the receiving blade53 is liable to be deformed. After transportation of the copier, thesupport 54 is coupled to the housing 51 so that the receiving blade 53abuts the photo-sensitive 10a. However, the end portion of the receivingblade 53, being abutted against the photo-sensitive material 10a, isbent inwardly of the housing 51, thus forming a gap between the bladeand the photo-sensitive material 10a as shown in FIG. 10. If a gap isformed, then when the toner is scrapped off with the main blade, it willdrop through the gap, thus smudging the transferring sheet conveyingpath or some other part of the copier which extends below the housing51.

SUMMARY OF THE INVENTION

An object of this invention is to eliminate the above-describeddifficulties accompanying a conventional cleaning unit in anelectrophotographic copier.

More specifically, an object of the invention is to provide a cleaningunit for an electrophotographic copier in which the receiving blade isprevented from being deformed when abutted against the photo-sensitivematerial.

Additional objects and advantages of the invention will be set forth inpart in the description which follows and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and attained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

To achieve the objects and in accordance with the purpose of theinvention, as embodied and broadly described herein, the cleaning unitfor an electrophotographic copier adapted to remove toner and developingmaterial from a photo-sensitive drum having photo-sensitive materialdisposed thereon from which a developed image has been transferred, ofthe invention comprises: a housing having an opening facing thephoto-sensitive material; a cleaning member provided in the housing, thecleaning member having an end portion which abuts against thephoto-sensitive material through the opening of the housing to scrapethe toner and developing materials off the photo-sensitive material; areceiving blade covering the lower portion of the opening and having anupper end portion abutted against the photo-sensitive material to allowthe toner and developing material scraped off by the cleaning member tofall into the opening; and a film-shaped reinforcing member bonded tothe surface of the receiving blade facing the inside of the housing.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one embodiment of the inventionand, together with the description, serve to explain the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is cross-sectional diagram illustrating the electrophotographiccopier with a cleaning unit constructed in accordance with the presentinvention;

FIG. 2 is an enlarged sectional view of the cleaning unit shown in FIG.1;

FIG. 3 is an enlarged diagram illustrating the components of thecleaning of FIG. 2;

FIG. 4 is a perspective view illustrating the components of the cleaningunit of FIG. 2;

FIG. 5 is a view taken in the direction of arrow V--V from FIG. 3;

FIG. 6 is a cross-sectional diagram illustrating a conventional cleaningunit;

FIG. 7 is an enlarged diagram illustrating the components of thecleaning shown in FIG. 6;

FIG. 8 is a view taken in the direction of arrow VIII--VIII in FIG. 7;

FIG. 9 is a perspective view illustrating the components of theconventional cleaning unit of FIG. 6; and

FIG. 10 is a sectional view illustrating a receiving blade in theconventional cleaning unit of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the present preferred embodimentof the invention, an example of which is illustrated in the accompanyingdrawings in which like reference characters refer to correspondingelements.

A cleaning unit according to the invention is used, for example, in anelectrophotographic copier such as shown in FIG. 1. The copier has aphotosensitive drum 10 which is turned in the direction of the arrow A,the axis of rotation being located at the center of the drum 10. Aphoto-sensitive material 10a is provided on the outer cylindricalsurface of the photo-sensitive drum 10. While the drum 10 is rotated inthe direction of the arrow A, the photo-sensitive material 10a isuniformly charged by a charging unit 11. Then, a predetermined image isprojected onto the photo-sensitive material 10a by an exposing unit 12,so that a latent image is formed in the photo-sensitive material 10a.The latent image is developed with toner by a developing unit 13. Then,the developed image is transferred onto a transferring sheet by atransferring unit 14. The transferring sheet is separated from thephoto-sensitive material 10a by a separating unit 15. After thedeveloped image is set by a fixing unit 16, the sheet is discharged outof the copier. The toner and other developing materials are then removedfrom the photo-sensitive material 10 by the cleaning unit 20 accordingto the present invention.

As shown in FIG. 2, the cleaning unit 20 of the present inventionincludes a housing 21 with an opening 21a; a cleaning member, namely, amain blade 22 for scrapping the remaining toner and developing materialsoff the surface of the photo-sensitive material 10a; a receiving blade23 for causing the toner and developing materials that are scraped offby receiving blade 23 to drop into the housing 21; and a reinforcingmember 24 attached to the receiving blade 23.

An opening 21a of the housing 21 is located between the separating unit15 and the charging unit 11 facing the photo-sensitive material 10a ofthe photo-sensitive drum 10.

The main blade 22 is pivotally supported in the upper portion of thehousing 21. More specifically, when the main blade 22 is pivoted in onedirection, its end portion 22a protrudes outside the housing through theopening 21 to contact the surface of the photo-sensitive material 10a;and when the main blade 22 is pivoted in the other direction, the endportion 22a is moved away from the photo-sensitive material 10a.

The receiving blade 23 is made of thermo-plastic polyurethane rubber orsimilar material. The receiving blade 23 covers the lower portion of theopening 21a as illustrated more clearly in FIG. 3. The upper end portionof the receiving blade 23 abuts against the photo-sensitive material 10asubstantially over the entire axial length.

As shown in FIGS. 4 and 5, a reinforcing member 24, of polyester film orsimilar material, is bonded to the rear surface of the receiving blade23 facing the inside of the housing 21. The reinforcing member 24 has acut in its upper end portion facing an image-forming region which isdefined on the photo-sensitive material 10a by both end regions in theaxial direction. The cut of reinforcing member 24 is arcuate at itscorners. Therefore, it is not necessary to bond reinforcing member 24 tothe rear surface of the receiving blade 23 which abuts against theimage-forming region of the photo-sensitive material 10a. Therefore, thereceiving blade 23 is not pushed against the image-forming region of thephoto-sensitive material 10a by the reinforcing member 24.

Seal members 25 are disposed inside the housing 21 facing the two endportions, or the two non-image-forming regions, of the photo-sensitivematerial 10a. Each of the seal members 25 is formed by sticking softfibers on the housing 21. The upper and middle portion of each of theseal members 25 abut against the photo-sensitive material 10a throughthe opening 21a, and the lower portion of each seal members 25 abutsagainst the reinforcing member 24. Accordingly, the seal members 25 andthe reinforcing member 24 push the receiving blade 23 against thenon-image-forming regions of the photo-sensitive material 10a in theaxial direction of the photo-sensitive material 10a. Therefore, thetoner and other developing materials which are scraped off with the mainblade 22 will never be scattered outside of the housing.

As shown in FIG. 2, a conveying roller 27 is arranged above a support 26which is engaged with the housing 21 at the lower end. Therefore, thetoner and other developing materials that drop into the housing 21 areconveyed by the conveying roller 27 into a used toner recovering unit 28which is disposed on the other side of the housing 21 opposite to theside where the photo-sensitive drum 10 is arranged.

Before the electrophotographic copier with the cleaning unit of thepresent invention is shipped out of the factory, a support 26 is removedfrom the housing 21 so that the receiving blade 23 is held away from thephoto-sensitive material 10a. Therefore, before operation of the copier,the support 26 must be engaged with the housing 21 so that the upper endportion of the receiving blade 23 abuts against the photo-sensitivematerial 10a of the photo-sensitive drum 10.

After the support 26 has been coupled to the housing 21, as describedabove, the copier is operated in the conventional electrophotographingmethod. That is, a toner image is formed on the photo-sensitive material10a, and the toner image thus formed is transferred onto a transferringsheet, providing a copied image. As the drum 10 rotates, the part of thephoto-sensitive material 10a from which the toner image has beentransferred is moved to the cleaning unit 20 according to the presentinvention.

In the cleaning unit 20, the blade 21 abuts against a rotatingphoto-sensitive material 10a and scrapes the remaining toner and otherdeveloping materials off the photo-sensitive material 10a. The toner andother developing materials that are scraped off are allowed to fall downthe receiving blade 23, abutted against the photo-sensitive material10a, into the housing 21. The scraped off material is then conveyed bythe conveying roller 27 into the used toner recovering unit 28.

In the cleaning unit of the present invention, the reinforcing member 24is bonded to the receiving blade 23 in the manner described above.Therefore, the cleaning unit overcomes the problem that occurs when thereceiving blade abuts against the photo-sensitive material, i.e.,deformation of the receiving blade causing a gap to be formed betweenthe receiving blade and the photo-sensitive material. Thus, the tonerwhich is scraped off the photo-sensitive material will not scatter upondropping through the gap onto the transferring sheet conveying path.

It will apparent to those skilled in the art that various modificationsand variations can be made in the cleaning unit of the present inventionwithout departing from the scope or spirit of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A cleaning unit in an electrophotographic copieradapted to remove toner and .[.developer.]. .Iadd.developing.Iaddend.material from a photo-sensitive drum having photo-sensitivematerial disposed thereon from which a developed image has beentransfererd, said cleaning unit comprising:a housing having an openingfacing said photo-sensitive material; a cleaning member provided in saidhousing, said cleaning member having an end portion which abuts againstsaid photo-sensitive material through said opening of said housing toscrape the toner and developing material off said photo-sensitivematerial; a receiving blade .Iadd.detachably coupled to said housing,.Iaddend.covering the lower portion of said opening and having an upperend portion abutted against said photo-sensitive material to allow saidtoner and developing materials scraped off by said cleaning member tofall into the opening; and a .[.film-shaped.]. reinforcing member.[.bonded.]. .Iadd.attached .Iaddend.to the surface of said receivingblade facing the inside of said housing, .[.an upper end portion of saidreinforcing member abutting against an image-forming region of saidphoto-sensitive material and being separated from said receivingblade,.]. said reinforcing member being arranged on a rear surface ofsaid receiving blade at a portion of said receiving blade where saidreceiving blade abuts against a non-image-forming region of saidphoto-sensitive material. .[.
 2. The cleaning unit as claimed in claim1, wherein said receiving blade to which said reinforcing member hasbeen bonded is detachably coupled to said housing..].
 3. The cleaningunit as claimed in claim 1, wherein said cleaning member is pivotallysupported in said housing such that when said cleaning member is pivotedin one direction, said end portion protrudes outside said housingthrough said opening to contact the surface of said photo-sensitivematerial, and when said cleaning member is pivoted in another direction,said end portion is moved away from said photo-sensitive material. 4.The cleaning unit as claimed in claim 1, further including a pluralityof seal means for pushing said receiving blade against an end portion ofsaid photo-sensitive material in an axial direction.
 5. The cleaningunit as claimed in claim 1, further including a used toner recoveringunit means, disposed on said housing opposite to said photo-sensitivedrum conveying means for carrying the scraped off toner and developingmaterial to said used toner recovering unit means.
 6. The cleaning unitof claim 1 wherein said reinforcing member includes a cut in said upperend portion facing a portion of said receiving blade where saidreceiving blade abuts against said image-forming region of saidphoto-sensitive material.
 7. The cleaning unit of claim 6 wherein saidcut in said reinforcing member is arcuate at corners of said reinforcingmember.